Terminal differentiation of the oocyte-cumulus complex in relationship with embryo development potential

Producing female gametes able to be fertilized and generate viable embryos requires that, beforehand, the oocytes have undergone optimal changes within the late growing and preovulatory follicles: at the chromatin level (meiotic divisions), at the cytoplasmic level (redistribution of organelles), and at the molecular level (from synthesis and storage of maternal transcripts to post-translational modifications). Surrounding cumulus cells reflect this evolution of the oocyte, due to the active and essential dialogue between the two compartments. Our studies aim to describe the late differentiation of the oocyte-cumulus complex in relation with the potential to sustain embryo development, and how this differentiation is affected by physiological or environmental factors (nutrition, endocrine disruptors...).

High-throughput technologies (transcriptomics, proteomics, lipidomics) have unveiled the expression profile and lipid profile in the oocyte-cumulus complex during maturation, to progress into understanding the underlying regulations. In particular, we analyze how genes controlling energy metabolism are involved in oocyte maturation (FA binding proteins, Tribbles etc). In parallel, novel genes preferentially expressed in the oocyte were evidenced (BCAR4, SLBP2…). Functional genomics is implemented to understand their role in oocyte maturation and/or embryo development. Beyond, they appear as candidate genes whose disturbance may cause female infertility. Finally, we develop methods to evidence and identify non-invasive biomarkers for predicting oocyte and embryo quality, such as transcripts or proteins expressed in the cumulus or metabolites (collaboration with Tours University Hospital).

Contact : rozenn.dalbies-tran[@]inrae.fr

Peyny, M., Jarrier-Gaillard, P., Boulanger, L. et al. Investigating the role of BCAR4 in ovarian physiology and female fertility by genome editing in rabbit. Sci Rep 10, 4992 (2020). https://doi.org/10.1038/s41598-020-61689-6